This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A271077 #26 Feb 26 2020 07:16:16 %S A271077 1,1,1,1,2,4,10,29,99,391,1775,9214 %N A271077 Number of pseudocomplemented lattices on n nodes. %H A271077 R. Belohlavek, V. Vychodil, <a href="https://doi.org/10.1007/s11083-010-9143-7">Residuated lattices of size <=12</a>, Order 27 (2010) 147-161 doi:10.1007/s11083-010-9143-7, Table 6. %H A271077 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pseudocomplement">pseudocomplement</a>. %o A271077 (SageMath) %o A271077 for i in range(0, 12): %o A271077 n = 0 %o A271077 for P in Posets(i): %o A271077 if P.is_lattice(): %o A271077 L = LatticePoset(P) %o A271077 if L.is_pseudocomplemented(): %o A271077 n += 1 %o A271077 print(n) %Y A271077 Cf. A006966. %K A271077 nonn,hard,more %O A271077 0,5 %A A271077 _Jori Mäntysalo_, Mar 30 2016